The Backlight Scanner is a photography tool that shields the light from your flashlight from the camera, while making sure you stay in the dark. The idea came from light painter Palateth (check his video on youtube:

https://youtu.be/oedIsFlaI8Q )

This version of the Backlight Scanner is 3d-printed with PLA and was designed in SketchUp. You'll find both files for the top and bottom cone attatched.

Supplies

Ø10mm round neodymium magnets

two-part epoxy or other strong glue

matte black paint

silver or chrome effect paint

sandpaper of various grits

3d-printer of access to a makerspace or FabLab.

Step 1: Check the Diameter of Your Flashlight

This file was made to fit my Fenix and Thrunite flashlights with a similar diameter front. However the flashlight didn't quite fit after printing and the space had to be sanded away a bit. Make sure to edit the top of the Backlight Scanner to fit your flashlight.

Step 2: Print Both Files

Print both files or have them printed. 15% infill is plenty sturdy. If you have a choice, go with black filament, since you'll be needing less paint later.

Avoid supports at the inner part of the small cone and the outer part of the large cone, as these will be the light reflectors and need to stay as smooth as possible.

Step 3: Glue the Magnets

The magnets will hold everything together, while making it possible to detach both parts during transport. I went for 10mm neodymium magnets and they are plenty strong. I used two-part epoxy.Make sure to note the polarity and attach magnets with the same polarity on each side of the Backlight Scanner!

Step 4: Paint, Sand, Paint, Sand, Paint....

Now it's time to sand the pieces and put down a layer of primer. Our goal is not to erase all printer lines, but to make sure no light shines through the cones. Printing everything in black PLA definitely helps here. You'll want the parts that'll be painted silver as smooth as possible. The parts that will be black can keep their printer lines. The printer lines might even help to keep the reflections to a minimum.

Step 5: Paint It Black...

Paint everything black

Step 6: Masking and Silver Paint

Mask of everything that needs to remain black and paint the inner small cone and a part of the outer large cone silver or chrome. The shinier the better. Your finished paint job should look something like this.